Frequently, a plurality of semiconductor components, to which are applied, together, a relatively high voltage with respect to the individual voltages that the different components have to withstand, are series-connected. Such is in particular the case for rectifying diodes series-connected between two terminals where a high voltage is applied (typically, several hundreds of volts). Each diode then sees a voltage lower than the total voltage. Ideally, the voltage seen by each diode, or more generally by each semiconductor element, corresponds to the total voltage divided by the number of components. In practice, due to technological dispersions in the forming of semiconductor devices, to manufacturing tolerances, and dispersions due to a temperature difference between each element in the application, there frequently is a voltage imbalance between the different diodes. This may lead to a situation where one of the diodes sees, between its terminals, a voltage which exceeds the voltage that it can withstand.
Systems that include a protection resistor connected in parallel with each diode to achieve a static balance and a capacitor connected for a dynamic protection have already been provided. However, devices based on resistors in parallel with the diodes have the major disadvantage of generating permanent losses through the resistors.